Tick salivary secretion during blood-feeding is crucial for successful tick feeding. Control of salivary secretion involves dopamine, which is the most potent inducer of tick salivation. Dopamine activates salivation by orchestrating two different physiological responses through two distinct dopamine receptors. In addition, the study demonstrated that two different types of cells in the salivary gland acini are responsible for each of the diverging physiological pathways: epithelial cells for inward fluid transport and myoepithelial cells for expelling fluid out through the acinar ducts. We were further interested in the downstream physiology of the dopamine receptors. A candidate gene (Na/K-ATPase), which is highly expressed in the salivary glands, was investigated. Immunoreactivity revealed that Na/K-ATPase is expressed in epithelial cells of acini. Ouabain, a Na/K-ATPase blocker, significantly suppressed both dopamine induced inward fluid transport and dopamine induced salivation in a dose-dependent manner. We measured the salivary contents to determine Na, K, and Cl ion, and protein concentrations. Treatment of ouabain at the low dose produced hyperosmolar saliva, but with same amount of protein as the control saliva. The results suggest that ouabain-sensitive Na/K-ATPase is the main downstream pathway for dopamine response in the epithelial cells of salivary gland for water transport, but not for protein secretion.
The pea leafminer fly, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), is a polyphagous pest attacking wide range of field and greenhouse crops and ornamental plants. Surprisingly, localized outbreaks with high population and heavy unique damage of leafminers were observed from the field survey of potato fields in the southern parts (Miryand and Goryeong) of Korea in 2012. L. huidobrensis was the responsible for those potato damages based on the morphological and genetic characteristics. Then after, it added a one more emerging species in Korean Liriomyza account. Infestation of L. huidobrensis was expanding and reported in major potato growing areas of the country. Genetic evidence showed the close relationship with Chinese L. huidobrensis population, so it might be invaded from China. As a new emerging pest, very few informations relative to this pest are available in Korean prospective. There is also significant potential for it to widen its distribution, as the Korean Peninsula is a hot spot of climate change, particularly global warming. There are a lot of challenges uprooting infront of researchers and growers. It is demanded to explore new secrets and to be ready to tackle of this invasive pest, L. huidobrensis.
The apple leaf miner, Phyllonorycter ringoniella(Lepidoptera:Gracillariidae),is an important pest of apple trees in Japan, Korea and China. It is very important to know the development time of overwinter pupae for predicting the adult spring emergence in apple orchard. In total 556 damaged leaves caused by P. ringoniella were collected three times in two locations, Pohang and Mungyeong, and then were reared in five incubators with 10, 15, 20, 25, and 30℃, RH 60±5%, and a photoperiod of 16:8 (L:D) h, respectively. There were larvae, pupae of P. ringoniella and its parasitoids inside these damaged leaves. Larval population was 44% inside the curled leaves, but found all dead. Pupal population was 41%, but 41% were found dead. Parasitism was 14.5% ranged from 4.5 to 17.9%. This means that the winter survival was only 23.9%. Surviving pupal developmental rate was linearly related to the temperature treated. Lower threshold was estimated to 3.58℃ with degree-day accumulation to adult emergence of 153.8 DD. From this information, adult emergence was predicted during early April. However this estimation was only based on the partial data from which current experiments are on-going. Further sophisticated research outcome will produce better understanding of the overwintering moth development and its modeling.
Transcriptome analysis was conducted for the identification of genes associated with insecticide resistance in Frankliniella occidentalis. Resistant strain (FO_RDAHC) exhibited 39.2- ~ 533-fold resistance to acrinathrin, spinosad, emmamectin benzoate and thiamethoxam compared with a susceptible FO_RDA strain. Average 7.6 million reads (± 5,068,895 reads) were obtained from the pyrosequencing and were assembled into the draft CDS database. Gene annotation was conducted by BLAST (UniProt), Pfam, FUNCAT and COG analysis. In the deferentially expressed gene (DEG) analysis, 838 genes were up-regulated and 815 genes were down-regulated over 2-fold ratio in FO_RDAHC strain. Highly up-regulated genes included genes encoding several cuticle-related proteins, cytochrome P450s, esterases and transporter genes. An autotransporter protein gene exhibited the highest up-regulation (596 fold) whereas a GMC oxido-reductase revealed the highest down-regulation (12 fold). Further study would be necessary to validate the actual transcript levels of DEGs and to investigate their functional roles in insecticide resistance.
Root-lesion nematodes, Pratylenchus sp., are recognized as one of the most important plant parasitic nematodes. They infest various crop plants and cause severe root damages which lead to the yield loss of agricultural crops. There are 72 species recorded in the world, but 14 species in Korea. Soil samples were collected from chrysanthemum cultivars in various regions. Morphological and molecular diagnosis firstly recognized two species as Pratylenchus kumamotoensis and P. pseudocoffeae in Korea. Morphologically, P. kumamotoensis characterized by pharyngeal gland lobes overlapping with intestine dorsally. P. pseudocoffeae, which is similar with P. coffeae, but pharyngeal gland lobes are longer than P. coffeae. In molecular diagnosis, nucleotide sequences of D2-D3 region (700-800 bp) within 28S rDNA and ITS region including ITS1, 5.8S and ITS2 (700-1,000 bp) between 18S and 28S rDNA were determined from collected samples. NCBI database comparison of D2-D3 of P. kumamotoensis and P. pseudocoffeae were 99% similar with those of corresponding species, respectively. ITS of P. pseudocoffeae was 99% similar within species. ITS sequence of P. kumamotoensis was firstly determined in this study. Distribution of P. kumamotoensis was only reported in Japan but P. pseudocoffeae is present in Japan and USA. Here we firstly report the presence of these two species in Korea.
대기 중 이산화탄소(이하 CO2)농도 증가가 왕담배나방의 산란과 발육에 미치는 영향을 400, 600, 1000 ppm CO2 환경에서 왕담배나방 2개 개체군(A, B)을 이용하여 인공 사육 조건에서 각각 조사하였다.
A개체군의 총 발육기간은 400 ppm, 600 ppm, 1000 ppm에서 각기 36.5일, 34.8일, 36.8일, B개체군에서 각기 37.8일, 34.5일, 37.4일로 두 개체군 모두 600 ppm에서 유의하게 짧게 나타났다(P < 0.01). 총 산란수는 A개체군의 경우 400 ppm, 600 ppm, 1000 ppm에서 각각 787.0개, 1225.6개, 926.2개로 400 ppm에서 유의하게 적었고 (P < 0.05) B개체군에서는 각각 843.6개, 1315.2개, 1307.6개였으나 통계적인 차이는 없었다. 성충의 수명은 CO2 환경에 따른 차이가 없었다. 왕담배나방의 내적자연증가율은 400 ppm, 600 ppm, 1000 ppm 농도에서 각각 A개체군은 0.093, 0.125, 0.107, B 개체군은 0.073, 0.113, 0.099로 모두 600 ppm에서 유의하게 높았다(P < 0.01).
CO2농도 변화에 따라 왕담배나방의 발육률 및 내적자연증가율은 유의하게 변하였다. 각 CO2 환경에서 얻은 결과값을 이용하여 추정한 이차회귀식에서 발육률은 701.0 ppm, 내적자연증가율은 744.5 ppm에서 피크를 보였다. 향후 예상되는 대기 중 CO2 농도의 변화는 왕담배나방의 개체군 증식에 직접적인 영향을 미치는 하나의 요소가 될 수 있는 것으로 보인다.
Baculovirus expression system has been used to produce functional proteins of various eukaryotic genes. A polydnaviral gene, CpBV-ELP1, was cloned in an alpha-baculovirus, Autographa californica multiple nuclear polyhedral virus (AcNPV), and expressed in Sf9 cells. CpBV-ELP1 protein was released into the culture medium due to its signal peptide. The culture broth containing CpBV-ELP1 was collected and fractionated with different concentrations of ammonium sulfate. Most CpBV-ELP1 was precipitated in 25-100% ammonium sulfate. The precipitate proteins were separated with a size exclusion chromatography sieving 100 kDa size. CpBV-ELP1 was eluted after relatively high molecular weight protein peaks. The fractions rich in CpBV-ELP1 were collected and further fractionated with an anion exchange chromatography. The purified CpBV-ELP1 was toxic to both larvae of Plutella xylostella and Spodoptera exigua by oral test used as leaf dipping method. A lethal median concentrations (LC50) were 7.5 ㎍/mL (95% CI: 1.2-24.3 ㎍/mL) for 2nd instar larvae of P. xylostella and 4.4 ㎍/mL (95% CI: 1.9-8.4 ㎍/mL) for 3rd instar larvae of S. exigua. These results suggest that CpBV-ELP1 may be applied to develop novel transgenic crops.
담배거세미나방(Spodoptera litura) 유충의 섭식 행동을 분석하기 위해 컴퓨터와 카메라를 이용하여 동영상을 촬영하고 이를 통해 연속적인 잎 면적 측정을 시도하였다. 잎 면적 측정은 담배거세미나방 2령충 유충을 이용하여 피망 잎 섭식흔을 1분 간격으로 일주일 동안 조사하였다. 유충의 먹이인 피망은 매일 교체하였고 잎 건조를 방지하기 위해 한천 배지위에 부착하여 제공하였다. 관찰 결과, 담배거세미나방 유충의 피망 잎 섭식 행동은 계단형의 불연속적인 섭식 형태를 보였다. 또한 섭식기와 비 섭식기가 뚜렷하게 구분되었으며 비 섭식기 이후 탈피를 하고 다시 섭식기에 들어서는 것을 확인할 수 있었다. 비교 실험을 위해 BT(Bacillus thuringiensis)제를 권장사용량의 절반 농도(500 ppm)로 처리한 결과, 대조구에 비해 섭식량이 감소하였으나 탈피 시기는 빨라진 것을 확인할 수 있었다.
Spotted wing drosophila, Drosophila suzukii, native to eastern and southeastern Asia, has become one of the most harmful pests causing serious damage to fruits such as blueberry, cherry, and others in Northern America and Europe. For quarantine sanitary purpose, methyl bromide (MeBr) has been used for a long time. However, it is under regulation because of its adverse effect of ozone layer depletion. Thus, alternative strategies to MeBr are needed to meet the quarantine requirement. In this study, we investigated effects of gamma ray irradiation (0, 50, 100, 200 and 300 Gy) on the development and reproduction of D. suzukii to offer a guideline in using gamma ray for dis-infestation of this pest. The higher doses of gamma ray caused more adverse effects on development and hatchability of D. suzukii. Development and oviposition of D. suzukii was significantly depressed at above certain doses, respective to each developmental stage. When eggs were treated with the doses of gamma ray, eggs hatched in some ratios at all doses. Even though some larvae developed to pupae under 100 Gy irradiation, all these pupae did not emerge to adults at all doses. When larvae were treated with gamma ray, some of them pupated at each doses. However these pupae did not emerge to adults at all under all doses. When pupae were irradiated, the emerged adults did not oviposit eggs above 100 Gy. When adults were irradiated, oviposition occurred normally, but fecundity and hatchability of the eggs were reciprocal to the doses.
A new gregarine species (Eugregarinida: Gregarinidae) was previously reported from daikon leaf beetle, Phaedon brassicae at Daegwallyeong in Korea. Here, we found another novel gregarine species from the striped flea beetle, Phyllotreta striolata (Coleoptera: Chrysomelidae). This paper describes the morphological and molecular-biological characteristics of Gregarine species associated to P. brassicae and P. striolata. The size and body shape at mature trophozoite stage were the main diagnostic characteristics of those species. Gregarines from P. brassicae were bigger size (100um) with square shaped body while Gregarines from P. striolata were slightly smaller size (80um) with egg shaped body. Based on the partial 18S rDNA sequence, gregarine species from P. striolata was grouped in eugregarine and also this new gregarine showed 85% homology that of the reported Gregarina sp. from P. brassicae. However, gut dissection result showed that each species had own gregarine parasite species association. These results were identical in local populations from three surveyed locations. There was positive relationship between infection rates and elevation for gregarine related to P. striolata. Therefore, we suggested that the gregarines and their coleopteran hosts have species-specific interaction via co-evolution.
Translational control is a strategy for various viruses to manipulate their hosts to suppress any acute antiviral activity. Some cys-motif genes encoded in polydnaviruses or teratocytes act as host translation inhibitory factor (HTIF) to defend the host antiviral activity. A novel cys-motif gene, TSP13, was encoded in the genome of an endoparasitoid wasp, Cotesia plutellae. TSP13 consists of 129 amino acid residues with a predicted molecular weight of 13.987 kDa and pI value at 7.928. Genomic DNA region encoding open reading frame is interrupted with three introns. TSP13 was expressed in Plutella xylostella larvae parasitized by C. plutellae. C. plutellae bracovirus (CpBV) was purified and injected to nonparasitized P. xylostella. In the virus-injected P. xylostella, TSP13 was shown to be expressed by RT-PCR analysis. Thus, TSP13 was turned out to be encoded in the proviral CpBV genome. TSP13 was cloned into a eukaryotic expression vector, which was then used to infect Sf9 cells to transiently express TSP13. The synthesized TSP13 was detected in the culture broth. Purified TSP13 significantly inhibited cellular immune responses. Furthermore, TSP13 entered the target cells and was localized in the cytosol. This study reports a novel cys-motif gene, which is encoded in CpBV genome localized on chromosome(s) of C. plutellae and replicated to be encapsidated in the episomal viral particles during parasitization.
미국선녀벌레 [Metcalfa pruinosa (Say, 1830)]는 북미 원산 해충으로서 2009년 서울, 경기, 경남 등 3개 시군구에서 처음 확인되었으며, 2015년 현재 52개 시군구로 급격히 분포 지역이 확대 되고 있는 침입 해충이다. 본 연구는 미국선녀벌레의 월동난의 휴면 종료 시기를 추정하고, 온도에 따른 발육 특성을 조사하고자 수행되었다.
월동난의 휴면 종료 시점을 추정하기 위해 2011년 2회, 2012년 8회, 2015년 5회 월동난을 채집하여 실내에서 가온하였으며, 2013년 채집된 월동난을 이용하여 10개 항온, L:D=14:10 조건에서 발육 특성을 조사하였다. 미국선녀벌레 월동난은 4월 상순부터 휴면이 종료되기 시작하여, 4월 하순경에는 대부분의 난들이 휴면에서 종료되는 것으로 추정된다. 월동난은 처리 온도 중 12.5℃와 35℃를 모든 온도 조건에서 약충으로 발육이 가능하였다. 온도에 따른 난 발육 기간은 4월 26일 채집된 월동난의 경우 15℃에서 46.9일로 가장 길었고 30℃에서 13.3일로 가장 짧았다. 선형모델을 이용하여 추정한 미국선녀벌레 월동난의 발육영점온도는 10.1℃였으며 유효적산온도는 252.5DD 였다. 온도에 따른 발육률을 설명하기 위해 사용된 Lactin 2 등, 4가지 비선형 모델 모두 r2=0.99 이상의 높은 모형적합성을 보여주었다. 2013년 경기도 수원지역의 온도 자료를 사용하여 월동난 부화시기를 추정한 결과 5% 누적 부화일은 5월 22일, 99% 누적 부화일은 6월 5일로 추정되었다.
이상의 결과들은 미국선녀벌레의 효율적인 개체군 밀도 관리 대책 수립을 위한 기초 정보로 사용할 수 있을 것이다.
Indianmeal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) is an important pest of stored grains products. As a natural enemy, an ectoparasitoid Bracon hebetor Say (Hymenoptera, Braconidae) has been used to control Lepidopteran pest insects. Venom from parasitoid female alters many physiological functions in host insects. However, mechanism of physiological response of host insects against envenomation and parasitization is not clear. Here we observed the effect of B. hebetor envenomation on the gene expression (shsp, hsp70, grp78 and hsp90) in P. interpunctella at different time intervals of post envenomation. Fifth instar day 5 larvae of P. interpunctella were used in experiment to observe the effect of envenomation. Our results showed that parasitoid envenomation affected the gene expression differently in host insect. This study will provide comprehensive insights on physiological and biochemical mechanism in host-parasitoid relationships.
The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex, including at least 24 biotypes which express different ecological and physiological characteristics. B. tabaci is one of the most serious pests in the horticultural crops in worldwide level. B. tabaci infests over 600 plant species and also indirectly damages plants by the honeydew excretion. Moreover, whiteflies transmit more than 100 plant viruses, especially begomoviruses. Tomato yellow leaf curl virus (TYLCV) which infested severely in tomato cultivars is transmitted by the vector insect, B. tabaci. Here, we demonstrated whether gene expression of B. tabaci is regulated by the oral ingestion of dsRNA. Double strand RNA (dsRNA) of heat shock protein 70 gene (hsp70) was produced from cDNA by using the specific primer. Whitefly adults were allowed to ingest sugar solution containing dsRNA for 3 hr in the two-layered parafilm feeding tube. Quantitative realtime PCR showed that whiteflies which ingest hsp70 dsRNA completely knockdown its transcript expression. Whiteflies ingestded dsRNA increased mortality by heat shock but not by cold shock. Further research will focus the role of hsp70 in various environmental stresses against insects.
The use of radar systems for entomological research offers new opportunities that allow continuous tracking of individual insects in natural settings. In particular, harmonic radar systems can be applied for small animals such as insects because the radar tag does not rely on battery power, allowing them to be light weight. To apply this technology, it is essential to develop procedures to securely attach radar tags on target insects and thereafter demonstrate no adverse effects of radar tag attachment on insect survivorship and behaviors. In this study, we developed procedures to securely attach harmonic radar tags on adult Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) and verified there were no detectable adverse effects of radar tagging on R. pedestris survivorship and walking or flight capacity. With the radar technique, future studies will focus on understanding dispersal capacity and pattern of R. pedestris in diverse landscapes. This will help enhance monitoring and management programs for this pest.
Essential oils from 22 plant species were tested for their insecticidal activities against spotted wing drosophila (SWD), Drosophila suzukii Matsumura, using fumigation and contact bioassay. Responses varied with the essential oils, their constituents and concentrations. Strong fumigation activities were observed from the essential oils of wintergreen (Gaultheria fragrantissima), croton (Croton anisatum) and star anise (Illicium verum). Strong contact activities were observed in the essential oils of oriental sweetgum (Liquidambar orientalis), cassia (Cinnamomum cassia), damask rose (Rosa damascena) and sandalwood (Santalum album). The compositions of these selected essential oils were identified using gas chromatographymass spectrophotometer. The compounds identified were tested individually for their insecticidal activities against SWD. Responses varied by doses for each compound. The results showed that natural materials are as effective as synthetic pesticides.
Cabbage is one of the major vegetable crops especially in Korea. Various insect pests intimidate the cabbage production. Moreover, an excessive spray of chemical insecticides leads to development of insecticide resistance as well adverse effects on environment and humans. The brassica leaf beetle, Phaedon brassicae, is a coleopteran pest. Both larval and adult stages feed cabbage. This study aimed to develop an effective microbial biopesticide against P. brassicae by adding immunosuppressive agent to Bacillus thurigiensis (Bt). To determine an optimal immunosuppressive agent, two bacterial species of Photorhabdus temperata subsp. temperata (Ptt) and Xenorhabdus nematophila were compared in their insecticidal activity against P. brassicae, and Ptt was selected. Among four subspecies of Bt, B. thuringiensis subsp. tenebrionis (Btt) was selected. Ptt bacterial culture broth possessed immunosuppressive agent(s) because the bacterial culture broth significantly increased other bacterial growth in P. brassicae hemolymph. When the Ptt broth was added to Btt, it significantly increased the insecticidal activity of Btt. Bt-Plus was prepared by mixing Btt and Ptt bacterial culture and sprayed the cabbage infested by P. brassicae. The Bt-Plus was much more effective than Btt treatment. This study reports a novel Bt insecticide to control P. brassicae.
To assess actual foliage damage due to potato leaf miner, Liriomyza huidobrensis (Blanchard), commercial potato pockets of Lalitpur, Kathmandu, Bhaktapur, Kavrepalanchwok, Sindhupalchwok and Makwanpur districts of Mid-Nepal were surveyed in 2009. Percent foliage damage analysis and ANOVA (with unbalanced frequency distribution) of multiple regressions of different factors were done to evaluate the level of damage and factors significantly influencing damage. Damage level was found more in lower altitudes (790-1568 meters above sea level) than in higher altitudes (1560-2610 meters above sea level). Similarly, lower leaves were more damaged than the upper ones. So, altitude and plant age were two factors influencing damage by test insect. Since the pest is becoming severe and can withstand chemical sprays, it is imperative to develop suitable IPM technique against this insect. Similarly, strict quarantine and awareness campaign against this insect pest are crucial to check its migration to virgin potato pockets.
여치류는 선조들에 의하여 식용으로 이용된 곤충이다. 여치류는 국내에 약50여 종이 기록되어 있는데, 그 중 개체수 밀도가 높아지고 있는 갈색여치(Paratlanticus ussuriensis)의 자원 이용성을 탐색하고자 하였다. 분류학적으로는 국내에 갈색여치가 1종만이 있다는 의견과 그와 더불어 팔공여치(P. palgongensis) 또한 실재한다는 주장이 엇갈리고 있다. 이에 갈색여치속에 속한 종의 다양성을 진단하고자 13지역 36개체를 4개의 미토콘드리아 유전자(COI, COII, ND1, ND2)로 분석하였다. 특히 메뚜기목에서 의도치 않게 자주 증폭되는 Numts는 long PCR법으로 제거한 후 Nested PCR을 통해 진본의 미토콘드리아 염기서열을 이용하였다. 4개의 유전자 마커 모두에서 갈색여치는 4개의 뚜렷한 묶음 그룹이 확인되었으며, 유전자별 최소 4%~9.8% 수준의 분화율 차이를 보였다. 또한 각 그룹은 지역적으로 3개의 서브그룹으로 나뉘는 현상을 보였다. 추후, 지역적인 샘플링을 추가하여 정밀성을 높인다면 보다 명확한 종 다양성이 밝혀질 것으로 사료된다.
한반도에서 오래 역사를 일궈온 우리 민족은 다양한 곤충을 기호적으로 먹거나 약리적 효과를 기대하고 약으로 이용하여 왔다. 이의 역사 기록은 여러 현대적 자료들을 통하여 식약용 곤충의 기록으로 언급되어 왔다. 하지만, 원전을 보지 않거나 또는 보았다 하더라도 분류학적 토대가 부족한 상태로 분석 없이 인용해 왔으며, 많은 경우는 2차 가공물을 토대로 재차 가공되기도 하였다. 최근에는 일본의 곤충자원 자료들이 우리 것들과 구분 없이 통합되어 우리 선조들이 자신들의 고유하고 다양한 종류들을 얼마나 어떤 방식과 이유로 먹었는지 혼란스러워졌다. 이번 연구에서는 근거자료로서 향약집성방, 세종실록지리지, 동의보감 등 조선시대 자료와 조선총독부조사자료, 선만동물통감 등을 포함한 근대적으로 해석된 자료를 총망라하였다. 이들 원전에서 식용과 약용으로 이용된 곤충자료를 모두 모아 분류학적으로 1차 분석하고자 하였다. 아울러 식용을 위한 조리법과 이용 방식 등에 대한 활용 방식에 대하여도 2차 정리를 시도하였다. 이를 통하여 한반도에서 이용된 식·약용곤충의 실체과 이용 방식을 밝혀 향후 식·약용자원 활용의 기초자료로 이용하고자 하였다.